Clinical metallic thermometer



(No Model.) 2 sheew-sliee 1.

W. E. EOWLE.

CLINICAL METALLIG THERMOMETER.

Patented Mar. 4. 1884.

(No Model.)

2 Sheets Sheet 2.

W. B. POWLE.

GLINIGAL METALLIC THERMOMETER.

Patented Mar. 4, 1884.

`Nrrn TILEIAM l. FOVLE, O F NEWTON, ASSIGNORv TO ROBERT M. MORSE, JR.

ATENT muon.

OF BOSTON, MASSACHUSETTS.

CLINICAL METALLIC THERMOMETER.

SPECIFICATION forming part i' Letters'- Patent No. 294,729, dated March 4, 1884.

' Application vfiled November 15, 1883. (No modell);

of the same.

My invention is an improved clinical. thermometer, in which an index-finger is moved by the lunequal expansion and contraction of different metals, united as laminze in a single strip.

The object oi' the invention is to make a very sensitiveinstrument, convenient in form,

and self-regulating, and to adapt it generally to the special requirements of a clinical thermometer.

In the accompanying drawings, Figure l is a side elevation of the device, on an enlarged scale, with the upper and lower portions of the case in section. Fig. 2 is a side elevation of the device on a smaller scale, case partly broken away. Fig. 3 shows on an enlarged scale the indeX-iinger and immediate operating devices. Fig. t is a horizontal section on line .fr x, Fig. 1. Fig. 5 is a detail view.

The same general form of laminated spring shown in an application filed by me in the United States Patent Office, of even date herewith, is in use in this invention. -It is marked A, and is contained in the lower part, b, a hollow stem, B, of the instrument. The upper part of the stem (marked a) is connected to the plate A,.on which the dial-plate is fixed.

i The guide-straps c c, attached to the upper section of the stem, prevent the outer case from touching the spiral coil, and by means of two pins, l l, set in a cross-piece attached to the lower ends of these strips, and entering a small block fixed to the lower end of the coil, the said lower. end is held from turning. To the upper end ofthe laminated coil is attached a staff, which is within the upper part of the case, and turns with the coil as the latter eX-' pands or contracts. It projects above the bottom plate of the bridge D, to which the plate A is fixed, and carries, secured on its upper end, an arm, d, which, as the staff turns, moves in a plane parallel with the plate A', and just underneath the same. As it thus moves it strikes against an arm, e, on the end of a shaft, E, and within its sweep, which latter has its bearings at the outer end in a small bracket, F, and at the inner end in a larger bracket, G. On the inner end of this shalt is staked a crown-wheel, H, which engages with a pinion, k, on the spindle, which carries the index-finger. The amount of motion which the arm d will impart to the small arm c by a given amount of movement of said arm l will depend upon the distance from the shaft E at 'which it strikes the said arme, The arm d is therefore provided with a joint, by means of y which its outer end may be raised or lowered, and thus the action of the hand is decreased or increased until its time rate of movement is obtained. The movement of the arm c is limited by means of a set -screw, j, in the outer bridge, so as to make the action equal and regular. If not properlyset by this screw, the instrument would move too fast at the commencement of its action, and too slowly toward the close. The shaft E is thus rocked in certain limits, and the wheel H is made large enough in relation to the pinion lc to give the necessary4 movement to the vindex-finger.

IThe dial-plate is marked into degrees from '90 to 110 Fahrenheit, and the degrees are subdivided into fifths or'tenths; but this may be varied, if found desirable.

This instrument is a registering one. The action of the increasing temperature'on the coil moves the arm d, rocks the shaft E by pushing aside the arm e, then leaving the arm e, and consequently the index-finger, at the maximum point attainedto indicate that point. If so desired, the hand' may b e held more lirmly, after it has reached the maximum point, by means of a brake, Z, in the form of a bellcrank lever. One arm presses upon the wheel H. The other is in the form ofa spring, against which the stem m of aknob, o, may be pressed. The movement ofthe spring-arm is limited by a stop, p.

In order to reset the instrument by bringing the linger back to 90o, I have provided a lever, t', the -outer end of which projects through the ease, and may be held by a catch, q. The inner end strikes against a pin prop- ICO the coil to the proper place for the inde.\iinv ger.

The mechanism is covered by a suitable cover, l?, which is slipped on over the stem, and into the upper part ot' which the glass top is screwed.

rlhc stem containing the coil is the only part of the instrument which need be in contact with the body ot' the patient, and its l'orm is adapted to the purpose.

I prefer to use l'or the coil lamina*y ot' steel and brass brazed together.

I claim as my invention* l. A clinical thermometer consisting otl a dial-plate having suitable index-iingcr, astem attached to the rear ot' thedial-platc, a. bimetallic spiral coil within said stem, and lixed thereto at its lower end, an arm connected to its upper end, and mechanism connected to the spindle ot' the index-Hilger, adapted to be struck and pushed by the said arm, whereby the said linger is advanced as the temperature ot' the coil rises, substantially as described.

2. ln combination, the hollow stem and coil having a stattl fixed to the upper end of said coil, an arm on upper end of said staff, a rocking shaft having an arm within the sweep of the stat'tarm, a crown-wheel on the inner end of the rocking shalt, and a pinion on the spindle ot' the indexdinger, all substantially as described.

3. In combination with thc rock-shaft of the thermometer, having` an arm, e, the jointed arm of the coil-stati', as and for the purpose set forth.

+L. ln a clinical thermometer, an :index-finger and a laminated coil, with intermediate mechanism connecting it to the -iinger, wherebythe movement ot' the coil pushes the finger over the dial, and a brake mechanism, the parts being combined and operating as dcscribed.

ln testimony whereof have signed my name to this specification in the presence of two subscribing witnesses.

VWitnesses:

A. LlNcoLx lfowLi-i, (l nono n ll. lolnxxa. 

